We propose to develop a new technique for delivering antitumor drugs to specified target tissues in order to reduce drug toxicity. This technique involves a biological carrier, a "lipsome." The foundation of this approach is cell biology, particularly in the areas of: memmbrane chemistry, membrane movement, and cellular enzymology. The main objectives of this proposal are the following: 1. To achieve selective tissue delivery of actinomycin D and adriamycin by modification of liposome surface properties. 2. To compare the cytotoxicity of liposome-encapsulated and nonencapsulated actinomycin D and adriamycin to animals. 3. To determine the quantitative uptake of liposome-encapsulated actinomycin D in different cell types of various tissues. 4. To study in vitro uptake of liposomes containing actinomycin D and adriamycin by various tumor cells; and to investigate factors affecting the kinetics of their uptake. 5. To test the therapeutic efficacy of liposome-encapsulated actinomycin D in the following tumors: a) melanoma B16; b) Ridgway osteogenic sarcoma. 6. To test the therapeutic efficacy of liposome-encapsulated adriamycin in the following tumors: osteogenic sarcomas; c) lymphoma; d) Lewis lung carcinoma. 7. To explore additional techniques of separating liposomes into small size range groups.